The present invention relates to vehicle occupant protection systems or other safety systems employing linear actuators to elevate a vehicle surface such as a hood, in the event of collision or impact with a pedestrian. Known linear actuators typically employ pyrotechnic means to activate a piston within an actuator. This increases the cost of manufacturing given that the gas generating composition must also be manufactured prior to insertion within the actuator. Further, shipping and handling may be more complex or complicated due to transportation and related regulatory requirements. Additionally, typical pyrotechnic compositions may exhibit untenable moisture sensitivity and increase the size of the actuator due to storage requirements within the actuator. It would therefore be an improvement to provide an alternative to the typical pyrotechnically actuated pistons.